Method of thickening aqueous formulations

ABSTRACT

A composition for thickening aqueous based personal care products is comprised of a cosolvent selected from the group consisting of a diol, the mono alkyl ether of a diol, a salt of a sulfated ethoxylated alcohol, a salt of a sulfated ethoxylated alkyl phenol, and a complex organic phosphate ester; water; a nonionic surfactant and, an ester of an ethoxylated polyol.

This application is a divisional of U.S. appl. Ser. No. 08/146,549,filed Nov. 2, 1993, now U.S. Pat. No. 5,501,813.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to thickeners for increasing the viscosity ofaqueous compositions. In particular, this invention relates tothickeners which are easily incorporated into aqueous-based cosmeticsand latex paints.

2. Description of the Related Art

Many aqueous systems require thickeners in order to be useful forvarious types of applications. Such aqueous-based systems as cosmetics,protective coatings for paper and metal, printing inks, and latex paintsall require the incorporation of thickeners in order to have the properrheological characteristics for their particular uses. Many substancesuseful as thickeners are known in the art. These include naturalpolymers such as casein and alginates, and synthetic materials such ascellulose derivatives, acrylic polymers, and polyurethane polymers. Somethickeners for use in personal care products such as shampoos, facialcleaners, liquid hand soaps, and the like require prolonged mixingperiods and high temperatures to be incorporated into the products to bethickened. In some instances, the effectiveness of some thickeners hasbeen found to be influenced by the components in the compositions to bethickened. Thus, there is a need for thickeners for aqueous-basedpersonal care products which are readily incorporated and whose efficacyis not affected by other components such as salts.

SUMMARY OF THE INVENTION

Highly efficient thickeners have been surprisingly discovered that areeasily incorporated into aqueous-based personal care formulations attemperatures as low as 20° C. and without the need for heating andprolonged mixing. These thickeners contain: (a) a cosolvent selectedfrom the group consisting of a diol, the mono alkyl ether of a diol, asalt of a sulfated ethoxylated alcohol, a salt of a sulfated ethoxylatedalkyl phenol, and a complex organic phosphate ester; (b) water; (c) anonionic surfactant having an HLB of less than about 14; (d) an ester ofan ethoxylated polyol having at least 3 alcohol groups and having degreeof ethoxylation from about 80 to about 400. The thickeners according tothe invention are very versatile in that they can be used to thickensuch personal care products as shampoos, liquid hand soaps, showersgels, facial cleansers, and bubble bath soaps while also functioning astemporary thickeners for acrylic latex paints.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Other than in the operating examples, or where otherwise indicated, allnumbers expressing quantities of ingredients or reaction conditions usedherein are to be understood as modified in all instances by the term"about".

The cosolvents which can be used according to the invention are selectedfrom the group consisting of a diol, the mono alkyl ether of a diol, asalt of a sulfated ethoxylated alcohol, a salt of a sulfated ethoxylatedalkyl phenol, and a complex organic phosphate esters which are a mixtureof mono- and di-esters of phosphoric acid wherein the ester groups areethoxylated alcohols or ethoxylated alkyl phenols or a combinationthereof.

A diol can be any saturated or unsaturated, linear, branched, or cycliccompound having 2 alcohol functionalities. Examples of such diolsinclude, but are not limited to, ethylene glycol, 1,2-propanediol,1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol,1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, 1,12-dodecanediol,2-methyl-1,2-propanediol, 1,2-cyclopentanediol, 1,3-cyclopentanediol,1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol,diethylene glycol, triethyleneglycol, PEG-200 (polyethyleneglycol-200),and PEG-400 (polyethyleneglycol-400).

The alkyl group of the mono alkyl ether of a diol has from 1 to 10carbon atoms and can be any mono ether derivative of any of the diolsset forth above or a mono ether of a polyethylene glycol having amolecular weight of less than 700. Examples of such compounds includebut are not limited to 2-methoxyethanol (the mono methyl ether ofethylene glycol), 2-butoxyethanol (the mono butyl ether of ethyleneglycol), butyl carbitol (monobutyl ether of diethylene glycol),butoxytriglycol (monobutyl ether of triethylene glycol), methoxy PEG-200(mono methyl ether of polyethyleneglycol-200), methoxy PEG-350 (monomethyl ether of polyethyleneglycol-350). In thickener compositions forpersonal care products, the preferred cosolvents are 1,2-propanediol,PEG-200, PEG-400, and methoxy PEG-350.

A salt of a sulfated ethoxylated alcohol can be the alkali metal sulfatesalt or ammonium sulfate salt of an ethoxylated alcohol wherein thealcohol is a saturated or unsaturated aliphatic alcohol having from 6 to22 carbon atoms or a phenol or an alkyl phenol. Such compounds areavailable commercially, for example from Rhone-Poulenc Surfactant andSpecialty Division, Cranberry, N.J., as Alipal® CO433 which is thesodium salt of a sulfated polyethoxynonylphenol, Alipal® CO436 which isthe ammonium salt of a sulfated polyethoxynonylphenol, Alipal® EO526sodium salt of a sulfated alkylphenoxypolyethyleneoxy ethanol.

Complex organic phosphate esters which are a mixture of mono- anddi-esters of phosphoric acid wherein the ester groups are ethoxylatedalcohols or ethoxylated alkyl phenols are available commercially, forexample from Rhone-Poulenc Surfactant and Specialty Division, Cranberry,N.J., as Gafac® RA600, Gafac® BH650, and Gafac® BI729, each of which isa free acid of a complex organic phosphate ester. The compositionsaccording to the invention can contain up to 25% by weight of any one ora combination of cosolvents.

The nonionic surfactant component according to the invention can be anynonionic surfactant or combinations thereof having an HLB value of lessthan 14 as determined experimentally or calculated by the followingEquations I or II

    HLB=E/5                                                    (I)

Equation I is used to calculate the HLB value of a surfactant where onlyethylene oxide is used to produce the hydrophilic moiety. In Equation I,E is the weight percent of the oxyethylene content. Equation II

    HLB=20(1-S/A)                                              (II)

is used to calculate the HLB of fatty acid esters of polyhydric alcoholswherein S is the saponification number of the ester and A is the acidnumber of the acid.

One class of particularly preferred nonionic surfactants are alkylpolyglycosides. The alkyl polyglycosides which can be used in thecompositions according to the invention have the formula I

    R.sub.1 O(Z).sub.a                                         I

wherein R₁ is a monovalent organic radical having from about 6 to about30 carbon atoms; Z is saccharide residue having 5 or 6 carbon atoms; ais a number having a value from 1 to about 6. The alkyl polyglucosideswhich can be used in the compositions according to the invention havethe formula I and are commercially available, for example, as APG®,Glucopon®, or Plantaren® surfactants from Henkel Corporation, Ambler,Pa., 19002. Examples of such surfactants include but are not limited to:

1. APG® 225 Surfactant--an alkylpolyglycoside in which the alkyl groupcontains 8 to 10 carbon atoms and having an average degree ofpolymerization of 1.7.

2. APG® 425 Surfactant--an alkyl polyglycoside in which the alkyl groupcontains 8 to 16 carbon atoms and having an average degree ofpolymerization of 1.6.

3. APG® 625 Surfactant--an alkyl polyglycoside in which the alkyl groupscontains 12 to 16 carbon atoms and having an average degree ofpolymerization of 1.6.

4. APG® 300 Surfactant--an alkyl polyglycoside substantially the same asAPG® 325 Surfactant but having an having an average degree ofpolymerization of 1.4.

5. APG® 325 Surfactant--an alkyl polyglycoside in which the alkyl groupscontains 9 to 11 carbon atoms and having an average degree ofpolymerization of 1.6.

6. Glucopon® 600 Surfactant--an alkyl polyglycoside in which the alkylgroups contains 12 to 16 carbon atoms and having an average degree ofpolymerization of 1.4.

7. Plantaren® 2000 Surfactant--a C₈₋₁₆ alkyl polyglycoside in which thealkyl group contains 8 to 16 carbon atoms and having an average degreeof polymerization of 1.4.

8. Plantaren® 1300 Surfactant--a C₁₂₋₁₆ alkyl polyglycoside in which thealkyl groups contains 12 to 16 carbon atoms and having an average degreeof polymerization of 1.6.

Other examples include alkyl polyglycoside surfactant compositions whichare comprised of mixtures of compounds of formula I wherein Z representsa moiety derived from a reducing saccharide containing 5 or 6 carbonatoms; a is zero; b is a number from 1.8 to 3; and R¹ is an alkylradical having from 8 to 20 carbon atoms. The composition ischaracterized in that it has increased surfactant properties and an HLBin the range of about 10 to about 16 and a non-Flory distribution ofglycosides, which is comprised of a mixture of an alkyl monoglycosideand a mixture of alkyl polyglycosides having varying degrees ofpolymerization of 2 and higher in progressively decreasing amounts, inwhich the amount by weight of polyglycoside having a degree ofpolymerization of 2, or mixtures thereof with the polyglycoside having adegree of polymerization of 3, predominate in relation to the amount ofmonoglycoside, said composition having an average degree ofpolymerization of about 1.8 to about 3. Such compositions, also known aspeaked alkyl polyglucosides, can be prepared by separation of themonoglycoside from the original reaction mixture of alkyl monoglycosideand alkyl polyglycosides after removal of the alcohol. This separationmay be carried out by molecular distillation and normally results in theremoval of about 70-95% by weight of the alkyl monoglycosides. Afterremoval of the alkyl monoglycosides, the relative distribution of thevarious components, mono- and polyglycosides, in the resulting productchanges and the concentration in the product of the polyglycosidesrelative to the monoglycoside increases as well as the concentration ofindividual polyglycosides to the total, i.e. DP2 and DP3 fractions inrelation to the sum of all DP fractions. Such compositions are disclosedin copending application Ser. No. 07/810,588, filed on Dec. 19, 1991,the entire contents of which are incorporated herein by reference.

Examples of combinations of nonionic surfactants include a mixture of analkyl polyglycoside and an ethoxylated alkyl phenol, a mixture of analkyl polyglycoside and an ethoxylated fatty alcohol, and the like.Combinations comprised of an alkyl polyglycoside of the formula I andnonylphenol EO-9 (nonylphenol ethoxylated with 9 moles of EO onaverage); an alkyl polyglycoside of the formula I and decyl alcohol EO-6(decyl alcohol ethoxylated with 6 moles of EO on average); arepreferred. The compositions according to the invention can contain up to60% by weight of any one or a combination of nonionic surfactants.

The thickener according to the invention contains a carboxylic acidester of an ethoxylated polyol. For purposes of the present invention, acarboxylic acid ester of an ethoxylated polyol can be a singlecarboxylic acid ester of an ethoxylated polyol or a mixture of a largenumber of such esters wherein each component of the mixture is acarboxylic acid ester of an ethoxylated polyol having a definite degreeof ethoxylation and/or a definite degree of esterification. For example,a sample of an isostearic acid ester of ethylene glycol having anaverage degree of ethoxylation of 100 may contain a single compoundwherein each molecule is a di-isostearic acid ester of ethylene glycolwherein each alcohol group is ethoxylated with 100 oxyethylene units.The sample may also contain a mixture of compounds comprised of at leastthe mono-isostearic acid ester of ethylene glycol having an averagedegree of ethoxylation of 100 and di-isostearic acid ester of ethyleneglycol having an average degree of ethoxylation of 100. The degree ofethoxylation is stated as an average because, in the ethoxylationreaction, a distribution of polyethoxylation is invariably obtained.Such esters can be made, for example, by esterifying an ethoxylatedpolyol having an average degree of ethoxylation of from 80 to 400 with afatty acid having from 6 to 22 carbon atoms. The esterification reactioncan be carried out by any means known to those skilled in the art suchas by direct esterification with a fatty acid or by transesterificationof a fatty acid ester or by reaction with a fatty acid halide. Anethoxylated polyol is any compound having at least 3 alcohol groupswherein the majority of the alcohol functionalities have been etherifiedwith polyoxyethylene. Examples of the polyols which can be used to makethe ethoxylated polyols according to the invention include, but are notlimited to, trimethylolethane[2-methyl-2-(hydroxymethyl)-1,3-propanediol], trimethylolpropane[2-ethyl-2-(hydroxymethyl)-1,3-propanediol], and pentaerythritol(2,2-dimethylol-1,3-propanediol), diglycerol (glycerol dimer),dipentaerythritol, glycerol, and the like. An alkyl polyglycoside as setforth above can also serve as a polyol which can be ethoxylated and usedin the compositions according to the invention. Ethoxylated polyols canbe made by any method known to those skilled in the art such as by thedirect ethoxylation of a polyol as disclosed in Example 1. The preferredesters of ethoxylated polyols are pentaerythritol PEG-120 tetra C12-C18ester which is an ethoxylated pentaerythritol having an average degreeof ethoxylation of 120 esterified with an average of 4 moles of fattyacid mixture comprised of fatty acids having from 12 to 18 carbon atoms;pentaerythritol PEG-90 tetra isostearate which is an ethoxylatedpentaerythritol having an average degree of ethoxylation of 90esterified with an average of 4 moles of isostearic acid; andpentaerythritol PEG-130 tetra isostearate which is an ethoxylatedpentaerythritol having an average degree of ethoxylation of 130esterified with an average of 4 moles of isostearic acid; andpentaerythritol PEG-120 tetra isostearate. The compositions according tothe invention can contain up to 50% by weight of any one or acombination of an ester of an ethoxylated polyol.

The amount of thickener according to the invention which can be used tothicken aqueous compositions such as personal care products whichincludes shampoos, facial cleaners, liquid hand soaps, and the like willvary according to the composition of the product to be thickened and isreadily determinable by one of ordinary skill in the art. A thickeningeffective amount will typically range from 0.1% to 5.0% by weight.

The thickener compositions according to the invention can be made bymixing the cosolvent, water, nonionic surfactant and, esterifiedethoxylated polyol using standard mixing equipment.

The following examples are meant to illustrate but not to limit theinvention.

EXAMPLE 1 Preparation of Pentaerythritol PEG-120 Tetraisostearate

In a 3 liter reaction flask equipped with an agitator, distillationcondenser, nitrogen and temperature inlets, 2,698 grams (30.6 moles) ofethylene carbonate was heated to 65°-70° C. Pentaerythritol (1,302grams, 9.57 moles) was added and the reaction mass was heated to100°-110° C. After adding 8 grams of potassium hydroxide, starting anitrogen sweep, and raising the temperature to 150°-160° C., thecontents were reacted for 2 hours. The temperature was raised to185°-190° C. and the reaction continued until a hydroxyl number of 810.7mg KOH/g was reached. A vacuum strip at 185° C. was used to remove anyvolatiles before the product was discharged. A portion of the reactionmaterial (260 grams, 0.939 mole, hydroxyl number=810.7 mg KOH/g) wastransferred to an ethoxylation vessel and 3.6 grams of potassiumhydroxide was added. Its contents were degassed and dried at 115°-120°C. to a moisture of 0.08%. Ethylene oxide was introduced at 140°-150° C.and reacted to a hydroxyl number of 43 mg KOH/g, at which time, thereaction was stopped and 3.8 grams of acetic acid was added. The producthad a final hydroxyl value of 43 mg KOH/g and an acid value of 1.63 mgKOH/g. In a 0.25 liter reaction flask equipped with an agitator, refluxcondenser, nitrogen and temperature inlets, 100 grams (0.077 equivalentsOH) ethoxylated pentaerythritol (hydroxyl number=43 mg KOH/g), 0.2 gramFascat-4100, 0.3 gram 37% hydrochloric acid, and 24.1 grams (0.076 mole)of isostearic acid having an acid value of 178.05 mg KOH/g were addedwere heated to 200° C. The reaction was stopped when the acid value wasless than 1.25 mg KOH/g.

EXAMPLE 2 Preparation of Pentaerythritol PEG-120 Tetralaurate

The procedure of Example 1 was repeated except that 0.076 mole of lauricacid was substituted for the isostearic acid.

EXAMPLE 3 Preparation of Pentaerythritol PEG-120 Esterified with A C₁₂-C₁₈ Fatty Acid Mixture

The procedure of Example 1 was repeated except that 0.076 mole of a C₁₂-C₁₈ fatty acid mixture was substituted for the isostearic acid.

EXAMPLE 4 Preparation of C₁₀ -C₁₈ Alkyl Polyglycoside PEG-120 Esterifiedwith Isostearic Acid

The procedure of Example 1 was repeated except that a C10-C18 alkylpolyglycoside was substituted for pentaerythritol.

EXAMPLE 5 Preparation of Pentaerythritol PEG-90 Tetraisostearate

The procedure of Example 1 was repeated with a pentaerythritolethoxylate having a hydroxyl number of 52 mg KOH/g. The ethoxylate wasreacted with isostearic acid at a 1:1 equivalent ratio. The final esterhad an acid value of 0.86 mg KOH/g.

EXAMPLE 6 Preparation of Pentaerythritol PEG-130 Tetraisostearate

The procedure of Example 1 was repeated with a pentaerythritolethoxylate having a hydroxyl number of 39 mg KOH/g. The ethoxylate wasreacted with isostearic acid at a 1:1 equivalent ratio. The final esterhad an acid value of 1.25 mg KOH/g.

EXAMPLE 7 Preparation of Thickener Concentrate

The products in Examples 1 and 3-6 were blended with different nonionicsurfactants, water, and cosolvents. The thickener compositions and theirdispersability in surfactant solutions are listed in Table 1. Tables 2and 3 lists thickening data of thickener compositions in shampooformulations.

EXAMPLE 8 Thickening a Latex Paint

A thickener concentrate (1.6 grams) having a composition of 40%decyl-6EO alcohol, 35% pentaerythritol PEG-120 tetraisostearate, 15%propylene glycol, and 10% water (Table 1, thickener j) thickened 60.0grams of a styrene-acrylic latex paint from 90 cps (containing nothickener) to 4,350 cps.

EXAMPLE 9 Thickening of an Alkyl Polyglycoside Surfactant

A thickener concentrate (1.6 grams) having a composition of 40% C₁₂ -C₁₆2EO alcohol, 35% pentaerythritol PEG-120 tetraisostearate, 15% propyleneglycol, and 10% water (Table 1, thickener m) thickened 60.0 grams ofPlantaren® 2000 Surfactant from 976 cps (containing no thickener) to1,480 cps.

EXAMPLE 10 Thickening of Shampoo Formulations Shampoo Formulation A

40% by weight of 26% sodium lauryl ether sulfate solution; 3% by weightof cocamide diethanol amine; and 57% by weight of water. The pH wasadjusted to 6.5 with citric acid.

Shampoo Formulation B

15.0% Plantaren® 2000 (50% decyl polyglucose solution)

15.0% Standapol® EA-2 (26% ammonium laureth sulfate)

12.5% Velvetex® BK-35 (cocamidopropyl betaine)

1.5% Nutrilan® I (hydrolyzed collagen)

56.0% water. The pH was adjusted to 6.5 with citric acid.

                                      TABLE 1    __________________________________________________________________________    Thickener compositions                      type of              % co-                  %   nonionic                            % nonionic                                  shampoo    Comp.        % ppeg-tis              solvent                  water                      surfactant                            surfactant                                  formula                                       soluble.sup.4    __________________________________________________________________________    a   40.sup.1              --  10  NP9   50    A    NO    b   35.sup.1              --  10  NP9   55    A    NO    c   30.sup.1              --  10  NP9   60    A    NO    d   30.sup.1              13.sup.13                  10  NP9   47    A, B YES    e   54    36.sup.15                  10  --    --    A, B NO    f   35    28.sup.13                   7  NP9   30    A, B YES    g   25    20.sup.15                  15  APG-225                            17.5  A, B YES                      DA6   22.5    h   25    20.sup.15                  20  APG-425                            12.5  A, B YES                      DA6 22.5    i   26    11.sup.15                  14  APG-625                            14.0  A, B YES                      NP9   35.0    j   35    15.sup.15                  10  DA6   40    A, B YES    k   35    15.sup.15                  10  C.sub.(12-14) -2                            40    A, B YES    l   35    15.sup.15                  10  S-7.sup.5                            40    A, B YES    m   35    15.sup.15                  10  C.sub.(12-14) -2                            40    B    YES    n   35    15.sup.15                  10  C.sub.(9-11) -6                            40    A, B YES    o   35.sup.2              15.sup.15                  10  DA6   40    A, B YES    p   35    15.sup.5                  10  DA6   40    A, B YES    q   35    15.sup.6                  10  DA6   40    B    YES    r   35    15.sup.7                  10  DA6   40    A, B YES    s   35    15.sup.8                  10  DA6   40    B    YES    t   35    15.sup.9                  10  DA6   40    B    YES    u   35    15  10  NP12  40    B    NO    v   35    15  10  T-80.sup.12                            40    B    NO    w   35    --  16  DA6   49    A, B NO, YES    x   35    15  10  S-9.sup.11                            40    B    YES    y   35.sup.13              15  10  DA6   40    A, B YES    z   35.sup.14              15  10  DA6   40    A, B YES    aa  35.sup.10              15  10  DA6   40    A, B YES    bb  35.sup.14              15.sup.16                  10  DA6   40    A, B YES    cc  50    37.sup.17                  15  --    --    A    NO    __________________________________________________________________________     Key to Table 1     PPEGTIS = pentaerythritol PEG120 tetra isostearate     PG = propylene glycol     NP9 = nonylphenol ethoxylate, 9 EO (HLB = 13)     NP12 = nonylphenol ethoxylate, 12 EO (HLB = 14.2)     DA6 = decyl alcohol ethoxylate, 6 EO (HLB 12.5)     APG = alkyl polyglycoside (HLB = 12-13)     C.sub.(12-14) -X = mixed linear ethoxylated alcohols, X moles EO     .sup.1 pentaerythritol PEG120 tetra C12-C18 ester     .sup.2 alkyl polyglucose ethoxylate isostearate     .sup.3 C10-C15 secondary alcohol ethoxylate, 7 moles EO     .sup.4 instant solubility in shampoo formula at 25° C.     .sup.5 butyl carbitol     .sup.6 PEG200     .sup.7 methoxy PEG350     .sup.8 ethylene glycol     .sup.9 butoxytriglycol     .sup.10 glucomate DOE120 (PEG120 methyl glucoside dioleate)     .sup.11 C10-C15 secondary alcohol ethoxylate, 9 EO (HLB = 13.5)     .sup.12 sorbitan monooleate PEG20 (HLB = 15)     .sup.13 pentaerythritol PEG90 tetra isostearate     .sup.14 pentaerythritol PEG130 tetra isostearate     .sup.15 1,2propanediol     .sup.16 complex organic phosphate ester     .sup.17 2.5% sodium lauryl ether sulfate, 2EO + 32.5% 1,2propanediol

                  TABLE 2    ______________________________________    Thickening Shampoo Formula A.sup.1                    %    Blends, Table 1 Active  Viscosity, cps    ______________________________________    Blank           --        25    f               65      3,300    g               65      4,530    h               60      5,000    i               75      5,120    j               75      5,280    l               75      5,800    o               75      1,650    y               75      3,400    z               75      10,300    Commercial      100     4,560    Thickener    ______________________________________     .sup.1 0.5% NaCl and 1.0% thickener

                  TABLE 3    ______________________________________    Thickening Shampoo Formula B.sup.1    Thickener from  %    Table 1         Active  Viscosity, cps    ______________________________________    Blank           --        208    f               65      4,240    g               65      3,350    h               60      2,700    i               75      2,800    j               75      3,100    k               75      5,850    l               75      3,100    m               75      9,400    n               75      4,200    o               75      2,300    p               75      2,600    q               75      3,400    r               75      3,600    s               75      4,950    t               75      3,480    w               84      3,660    x               75      4,050    y               75      2,900    z               75      5,500    aa              75      1,450    Commercial      100     2,920    Thickener    ______________________________________     .sup.1 0.5% thickener

The following comparative examples show the thickening effect of thesame esterified ethoxylated polyol by itself and when incorporated intoa composition according to the invention. A thickener according to theinvention which contained pentaerythritol PEG-130 tetra isostearatedissolved readily at room temperature in a typical shampoo formulation.Pentaerythritol PEG-130 tetra isostearate alone did not dissolve in atypical shampoo formulation and dissolved only at elevated temperaturesand with difficulty.

COMPARATIVE EXAMPLE 1

About 3.4 grams of a thickener z from Table 1 (containing 35%pentaerythritol PEG-130 tetra isostearate) were added to 60 grams ofshampoo formulation A. The thickener dissolved instantly in the shampooto form a thickened solution having a Brookfield viscosity of 26,750 cps(#4 @12 rpm @25° C.).

COMPARATIVE EXAMPLE 2

About 1.2 grams of pentaerythritol PEG-130 tetra isostearate were addedto 60 grams of shampoo formulation A. The thickener dissolved in theshampoo after heating at 70° C. for one hour to form a thickenedsolution having a Brookfield viscosity of 27,750 cps (#4 @12 rpm @25°C.).

COMPARATIVE EXAMPLE 3

About 1.2 grams of pentaerythritol PEG-130 tetra isostearate were addedto 60 grams of shampoo formulation A at a temperature of 25° C. Thethickener did not dissolve in the shampoo after mixing at 25° C. for 24hours.

What is claimed is:
 1. A method of thickening an aqueous-basedformulation which comprises adding to said aqueous formulation athickening-effective amount of a composition comprising: (a) from about10% to about 25% by weight of a cosolvent selected from the groupconsisting of a diol, the mono alkyl ether of a diol, a salt of asulfated ethoxylated alcohol, a salt of a sulfated ethoxylated alkylphenol, and a complex organic phosphate ester; (b) from about 5% toabout 25% by weight of water; (c) from about 20% to about 60% by weightof a nonionic surfactant having an HLB of less than about 14; (d) fromabout 25% to about 60% by weight of an ester of an ethoxylated polyolhaving at least 3 alcohol groups and having degree of ethoxylation fromabout 80 to about
 400. 2. The method of claim 1 wherein said nonionicsurfactant is an alkyl polyglycoside of the formula I

    R.sub.1 O(Z).sub.a                                         I

wherein R₁ is a monovalent organic radical having from about 6 to about30 carbon atoms; Z is saccharide residue having 5 or 6 carbon atoms; ais a number having a value from 1 to about
 6. 3. The method of claim 2wherein said nonionic surfactant is an alkyl polyglycoside wherein thealkyl group contains 8 to 10 carbon atoms and having an average degreeof polymerization of 1.7.
 4. The method of claim 2 wherein said nonionicsurfactant is an alkyl polyglycoside wherein the alkyl group contains 8to 16 carbon atoms and having an average degree of polymerization of1.6.
 5. The method of claim 2 wherein said nonionic surfactant is analkyl polyglycoside wherein the alkyl groups contains 12 to 16 carbonatoms and having an average degree of polymerization of 1.6.
 6. Themethod of claim 1 wherein said cosolvent is 1,2-propanediol, PEG-200,PEG-400, or methoxy PEG-350.
 7. The method of claim 6 wherein saidcosolvent is 1,2-propanediol.
 8. The method of claim 1 wherein saidcosolvent is the sodium salt of a sulfated polyethoxynonylphenol, theammonium salt of a sulfated polyethoxynonylphenol, sodium salt of asulfated alkylphenoxypolyethyleneoxy ethanol.
 9. The method of claim 1wherein said cosolvent is a complex organic phosphate ester.
 10. Themethod of claim 1 wherein said ester of an ethoxylated polyol ispentaerythritol PEG-120 tetra C12-C18 ester, pentaerythritol PEG-90tetra isostearate, pentaerythritol PEG-130 tetra isostearate orpentaerythritol PEG-120 tetra isostearate.
 11. The method of claim 1wherein said nonionic surfactant is a combination of nonionicsurfactants selected from the group consisting of: (a) a mixture of analkyl polyglycoside and an ethoxylated alkyl phenol; (b) a mixture of analkyl polyglycoside and an ethoxylated fatty alcohol.
 12. The method ofclaim 1 wherein said nonionic surfactant is a combination of nonionicsurfactants comprised of decyl alcohol EO-6 and an alkyl polyglycosidewherein the alkyl group contains 8 to 10 carbon atoms and having anaverage degree of polymerization of 1.7.
 13. The method of claim 1wherein said nonionic surfactant is a combination of nonionicsurfactants comprised of decyl alcohol EO-6 and an alkyl polyglycosidethe alkyl group contains 8 to 16 carbon atoms and having an averagedegree of polymerization of 1.6.
 14. The method of claim 1 wherein saidnonionic surfactant is a combination of nonionic surfactants comprisedof nonyl phenol EO-9 and an alkyl polyglycoside wherein the alkyl groupscontains 12 to 16 carbon atoms and having an average degree ofpolymerization of 1.6.
 15. The method of claim 1 wherein said nonionicsurfactant is a combination of nonionic surfactants selected from thegroup consisting of: (a) an alkyl polyglycoside and nonylphenol EO-9;(b) an alkyl polyglycoside and decyl alcohol EO-6.
 16. The method ofclaim 1 wherein said ester of an ethoxylated polyol is present in anamount up to 50% by weight.
 17. A method of thickening an aqueous-basedformulation which comprises adding to said aqueous formulation athickening-effective amount of a composition comprising: (a) from about1.0% to about 25% by weight of 1,2-propanediol; (b) from about 5% toabout 25% by weight of water; (c) from about 20% to about 60% by weightof a nonionic surfactant selected from the group consisting ofnonylphenol EO-9, decyl alcohol EO-6, an alkyl polyglycoside of theformula I

    R.sub.1 O(Z).sub.a                                         I

wherein R₁ is a monovalent organic radical having from about 6 to about30 carbon atoms; Z is saccharide residue having 5 or 6 carbon atoms; ais a number having a value from 1 to about 6, and combinations thereof;(d) from about 25% to about 60% by weight of an ester of an ethoxylatedpolyol selected from the group consisting of pentaerythritol PEG-120tetra C12-C18 ester, pentaerythritol PEG-90 tetra isostearate,pentaerythritol PEG-130 tetra isostearate, pentaerythritol PEG-120 tetraisostearate and combinations thereof.